Security testing is used to identify vulnerabilities, assess risks, and ensure the protection of applications, networks, and user data. QA teams employ techniques like penetration testing, vulnerability scanning, and security audits to detect and mitigate potential threats. Advanced tools such as OWASP ZAP, Burp Suite, and Nessus help in analyzing security loopholes and ensuring compliance with industry standards. By integrating Security Testing into the software development lifecycle (SDLC), it helps businesses prevent data breaches, strengthen application security, and maintain user trust in an increasingly threat-prone digital environment.